The invention relates to a gangway or the like for providing ready and safe boarding access between the docking area or pier and a vessel at the dock.
When a vessel, such as a tanker, is moored at the docking area or pier in its loaded condition it will be relatively low in relationship to the height of the pier, but as a vessel is unloaded, the angle of elevation of the ship relative to the pier will become much greater. This change in the disposition of the angular elevation between the vessel and the pier can also occur as a result of providing cargo into the unloaded vessel or as a result of changes in the tide of the water basin itself. As a result great difficulty has been encountered in providing a gangway which will provide access between the docking area and the vessel at all positions of elevation of the vessel relative to the pier itself.
Heretofore attempts have been made to overcome these difficulties in a variety of fashions as, for example, by means of a sliding gangway arrangement or by the provision of telescoping or nesting extensions for the gangway. Such attempts however did not provide for an adjustment of the angular disposition of the gangway while maintaining the gangway in a steady, straight and non-twisting position despite the motion of the vessel laying at times in moving water. Furthermore, the prior attempts to solve the foregoing problems were not economical and lacked safety and other necessary features.
As a consequence, it is the object of the invention to provide a gangway or transfer bridge between the deck of a vessel and the docking surface by means of which a reasonable access angle is continuously maintained between the vessel deck and the docking surface.
It is a further and very improtant object of the invention to provide a gangway in which the free end is of such structure that it precludes any chance of tortional twist of the gangway relative to the place on which the free end of the gangway is rested.
Another object of the invention is to provide a gangway which while eliminating such tortional twist, nevertheless rides or moves back and forth freely to maintain an access angle which can be easily traveled between the vessel and the docking region.
Still another object of the invention is to provide a gangway which is relatively economical to construct and whose supports may be placed upon existing pier structure.